Our data valuation function exploits the negative \({\text{MMD}}^2_b(\mathcal {F}, S, T)\)  (REF ) w.r.t. reference dataset \(T\) :A similar form to (REF ) is considered in another work with a different focus on interpretable ML [1]}.
\(\begin{array}{rl}v(S) :=&\hspace{-6.82864pt} \displaystyle \left\langle t^{-2}1_{[x, x^{\prime }\in T]}, \mathbf {K} \right\rangle - {\text{MMD}}^2_b(\mathcal {F}, S, T) \vspace{1.42262pt}\\=& \hspace{-6.82864pt}\displaystyle \left\langle {2}(st)^{-1} 1_{[x \in S, x^{\prime }\in T]} - s^{-2} 1_{[x, x^{\prime } \in S]}, \mathbf {K} \right\rangle \end{array}\) 
